Circuit boards with which this invention finds use may take the form of thick film substrates, printed circuit boards, or the like. Irrespective of the type of circuit board, it will normally carry a number of electrical components mounted on its surface, with plated electrical conductors connecting the components in pre-arranged patterns. Typically, such a circuit board also includes terminals or pads to which external wires must be bonded to make electrical connection with the components mounted on the board.
In the manufacture of products using such circuit boards, it is desireable that the external wires be easily and rapidly bonded to the circuit board terminals in a manner which holds down the cost of the manufacturing process. It is also important that the bonded wires be mechanically held in position during and after the bonding process to protect them from being accidentally pulled away from their terminals and to eliminate mechanical stress from being coupled from the wire to the terminal, and thence to the circuit board itself. Stated differently, the bonded wires should be provided with strain relief.
In some applications, the circuit board may be carried inside a housing, thus requiring that the external wires pass through apertures in the housing to make connection to the terminals on the circuit board. Even in this application, the requirements of easy and rapid wire bonding should still be satisfied, and the circuit board should still be protected from mechanical stress applied to the wires, as discussed above.
Conventional techniques for effecting the type of circuit board assembly described above have proved to be inadequate either in terms of cost, required assembly time, or lack of sufficient strain relief.